Southern California -- this just in

Los Angeles police detectives investigating the so-called "Grim Sleeper" killings have received more than 40 calls from people asking them to investigate decades-old unsolved homicides and sexual assaults involving their loved ones.

Phones at the task force, which was set up in 2007 to investigate dozens of unsolved homicides in South Los Angeles, have been ringing nonstop since last week when the LAPD announced the arrest of Lonnie David Franklin Jr.

"The conversations have been emotional," said Det. Dennis Kilcoyne, who is heading the investigation into the killings.

Franklin, a former city sanitation worker, has been charged in connection with the slayings of 10 women between 1985 and 2007. He was dubbed the "Grim Sleeper" for the long and seemingly inexplicable gap between the initial set of murders that ended in 1988 only to resume a decade later.

LAPD Chief Charlie Beck said last week that investigators may be able to close some of those gaps by uncovering additional killings linked to the suspect, although he acknowledged it won't be easy.

The LAPD is already in the process of reexamining 30 unsolved homicides that could have been carried out by Franklin. They all have similar characteristics, including location, method and the victims' backgrounds living on the margins of society.

The unsolved cases are considerably more challenging because they lack DNA evidence and occurred when several serial killers were striking the Figueroa corridor, Inglewood and unincorporated L.A. County, detectives said.

Kilcoyne said the priority is to put together a criminal case against Franklin. But he said families seeking answers to unsolved murders can expect call backs as detectives look into every case no matter how scant the evidence.

"The families are going to get first-class attention from us for each and every one of these cases," Kilcoyne said. "But they have got to be patient with us. This is a massive undertaking."